Signal system for excavators



Sep@ 27,

s; v'fAUsT SIGNAL SYSTEM FOR EHCAYATORS Filed June 1S, 1936 worm INVENTOR. Ek wiyr fram??? QQ/@Wm ATTORNEY.

Patented Sept. 27, i933 SIGNAL SYSTEM FR EXCAVATORS Charles I. Mausi,Summit, N. 5.

l2 Claims.

Shis invention pertains, generally, to electiicn signal systems, and theinvention has reference. more-particularly, to n novel signal systemadepteri for use in connection with excavators used 5. icr undergroundwort: und particularly in excarating in earth and ft? The function ofthis invention is to indicate y signal to the operator Whenever the toolmrt of me excavating machine approaches or contacts lith existingservices in itl the earth or till, 'whereby the operator may telcoproper precautions to rrotcct such services from injury.

The Word service or service member, as herein contained. is intended toapply to any .existing l5' pipe, conduit. duct, 'frire or cable in theearth or ll usciul .for such services :is electricity. telcphone,telegraph. tretlic signal systems, tire alarm systems. policecommunication systems, gas. water. trolley return feeds, sewers anddrains. 9.o' The v.verd machine es herein contained shall be understoodto apply to any machinery'which is used for excavating. digging.scratching. plowing, boring, pushing er tunneling in earth end fill. Theword machine simil also be understood 25 to include such machinery :islndder type dltchers. crawler and wheel mounted types of cranes. withshovels, drag line scoops, clamp shell buckets. orange peel buckets.pull scoop buckets.- backhoe buckets.` trench hoe buckets, post, holediggers, 3G boring machines, tunneling machines and pushing machines.The 'word tool es herein contained simil be understood to apply to thatpart oi any machine which does the actual wort: in the earth :md till,such as the boom and bucket, boom and :s shovel, or shaft and auger.

In towns and municipalities, many servicesl generally exist understreets, walks and other plots of ground. The exact positions,directions. slopes, bends and connections oi such services 4g in mostcases are not accurately known, as in some instances only generallocations have been recorded and in others. rccrrds and land marks havebeen lost. For numerous reasons such loealities must be excavated, etc.,for new services, i5v extensions, repairs, changes or replacements.Hcretoi'ore, machines for such work have been wry limited in applicationdue to the hazard of damaging existing services or due to slow'. highcost operation of the machines to avoid injuring 5 such services, 'Thisinvention will hermit much broader application of machines forunderground work where underground services may he encountered. Sometypes oi mxchincs can be utillzed to great advantage around serviceswithout 5 datuioge thereto, providing the operator is given anindication oi' the approach to and contact `with such services.

One object of this invention is to provide signal means for suitablyindicating or signaling to the operator of the: 'nnchine the relativenearness 5 of a service the tool approaches the saine. thereby pcrznltrgfairly rapid ori-erationl oi the machine uni." t 1e tool gets very closeto the service, whereupon the operator een exercise caution :ind reducespeed. IG

Another object. of this` invention is to permit on adjustment if thesignal system so that the same bt-lfzns th r'z'icate et n greater orlesser dis tance oi the tooi no the. services, whichever is de sircd.tl.: said slcnsl system being ndapcd to inl5 cil-cate relative distancesoi the tool to the services hy the automatic change of sound volume,frequency or visual indication.

Still another object o' this invention is to provide si novel excavatorsignal system that docs not 2 cause the operator to detract hisattention irorn the operation of the tool. for whether the signal.device be audible or visual. or n combination thereof. the said deviceis located close to und in un advantageous position for the operator.9,5 thus preventing foreign sounds such as created by the machine.trucks, trolley cnrs, trains. ctc., from interfering with the signals.

Another obect ci this invention lies in the provision oi n novelexcavator signal system that 1 30 is oi simple construction and isreliable and economical in operation. the seid system being adapted tobe readily tested i'or service signal at any time to be sure that allparts are ready for operation. 35

till another object of this invention is to prvide for the automaticsupervision of the cornplete circuit by'way of a constant visual oraudible indication.

Other objects and advantages will become np- 40' parent from thespecification, taken in conriec tion with the accompanying drawingwherein the invention is embodied in denite form. l

Fig. i is a schematic view illustrating anexcarotor in use and equippedwith the novel signal 45 system of this invention. i

Fig. 2 is a wiring diagram o one form of signal system of thisinvention` 3 is o wiring diagram of a slightly modifie form of theinvention, and ,50

Fig. iis a wiring diagram illustrating the preierxed form of theinvention.

` Similar chnmctcrs of reierer'zc are employed in the above views toindicate corresponding parts. L g de .f, .......rn .Ji-i..

fui

:zoomer u fier; however, other parts of the circuit can he used foreither volume or ireouency control. such as the control connected in themicrophone cir cuit. heater circuit, or generator grid circuit. Manyradio hook-ups can be'made with and without. tube amplification and withmore stages of amplification to suit the requirements.

In Fig. 4. G and ii are a source of electrical energy such as threebatteries consisting of 6 volts, 223 volts. together designated as 6,and 221]; vclts, designated B', or a Gvelt storage battery vdth a motorgeneratorset [er voltage conversion may be used. '.vhile 'l is a tut-oilswitchfor thc source oi energy. AQOOchm rheostattiis used for simulatingthe changes oi earth resistance when adjusting the signal device for theproper signal to the -desired earth resistance. Icheostat. 8 contains anopen-circuit point and the rheostat is normally st: on this open-circuitposition. A microphone fr loud speaker or other sound devic:I such es abell 8 for conversion of electrical energy' into an audible signal, or aset of relays and lamp.; for conversion of electrical energy into avisible signal may be employed in lieu oi Q. A ground connection ii oithe control circuit to the metallic frame of the machine is used, a partoi the frame which nas good metallic connection with the tool beingemployed. The earth part of the control circuit is designated i2 andseparat-es the tool from thenear-by services. A connection oi' thecontrol circuit to one or more parts oi a service system, such as e firehydrant i? or gas or water pipe in a building or street. is crzztioged.A conventional A. C. generator such as an audio oscillator 2 or a powerdriven generator is used for supplying a. step-down transiormer 23 inthe control circuit vwith an audio frequency signal. plies currentthrough ground l2 to e. step-up transformer 29 in the signal controlcircuit. The output of transformer 2B is supplied to a conventional typeot audio ampliiier 3Q consisting of one or more stages ci ampliiicationand having the signal device 9 in the plate circuit thereof. Resistors3i and S2 serve for adjusting the sig nel volume to suit the desiredindication of greater or leas distance of soil separation between thetool and the services.

When the tool of the machine is not in the earth. there is enoughleakage in the radio circuit te operate the device 9 or loud speakerfaintly. When the tool contacts with the soil the audibiiity increasesslightly. Under the latter condition, the operator is automaticallygiven supervisory indication that 1li connections are complete and thatthe stt is functioning. This feature is very important, as occasionallythe wire connecting the signal device t) the service systern'becomesbroken or disconnected. As the tool approaches a service, the signalgets louder and louder so that., in use, the operator can tell just hownear he is to a service, and hence avoid striking the same with thetool.

As many changes could be made in the above construction and manyapparently widely difierent. embodiments of this invention Could bemarie without; departing from the scope thereof. it is intended that allmatter contained in the above description or shown in the accompanyingdrawing shall be interpreted as illustrative and not in a limitingsense.

What is claimed is:

I. in combination with an excavator having a digging toni, a signalsystem for notifying the operator when the tool approaches a. serviceTransformer 28 sup-v member and the ncarness of approach, comprisineasigna! device and a circuit for controlling me operation oi the signaldevice, said circuit including a source oi current, the excavatordlgging tool, th variable resistance oi the layer of earth between thedigging tool and the service.

member. and the service member, the constants of the circuit and thecharacter of the signal de vice being such that the signal device iseiIectively operated at a predetermined distance of approach or' thedigging tool i the service member and is operated with increasedintensity upon further approach.

2. In combination with an excavator having a digging tool, a signalsystem for notifying the operator when the tocl approaches a. servicemember, thereby giving the operator ample warning to prevent the toolfrom contacting a service t member and enabling the maximum digging byan excavator without musing;r damage to rnetalllc service members, the.said signal system comprising a signal device and a. circuit forcontrolling the operation oi' the sipnal device, the said circuitincluding a source of electrical current, the excavator digging tool,the variable resistance oi the layers of earth and/or illl between thedigging tool und a service member, the return connection between thesaid signal device and a part oi the said metallic service member, andthe electrical connection from the said signal device to the tool. theconstants of the circuit and the characteristics of the signal devicebeine such that the signal device is eiectlvcly operated at variouspredetermined distances of approach of the tool to the service member,the signal device operating continuously with increased intensity oisignal as the tool moves closer to the service In mber, therebysignifying to the operator that the tool is working in a caution zonethat may extend from a few inches to within a ien' feet from the servicemember, the range of the caution zone being predetermined by theoperator, the signal device having: e means of adjustment or the desiredrange of th zone to suit the type and condition or the earth or ll andto suit the type and speed of the excavator.

3. In a sien-ul syst-ern for excavators having;` an earth excavatingical, s. thermionlc oscillator for producing an audio frequency signalvoltage, a circuit including a transformer energized by said signalvoltage, said circuit including the excavator tool, a. service memberend the earth extending between said tool and the service morn bei',together with an output transformer, and an audio signal device fed fromsaid circuit outout transformer. the constants of the circuit and thecharacter of the signal device being such that the signal is eilectivelyoperated at a predetermined distance of approach of the digging tool tothe service member and is operated with increased intensity upon furtherapproach.

4. In a. signal system for excavators having an earth excavating -tool,generating means for producing an audio icequency signal voltage, a.circuit energized by sait; signal voltage, said circuit including1 theexcavator tool, a service member and the earth extending between saidtool and the service member. and an audio'signal dcvice controlled fromsaid circuit, the constants f the circuit :ni the character of thesignal device being such that the signal is efiecively operated at a phdetermined distance of approach oi the digging ooi to the service memberand is operated with increased intensity upon further approach.

5. In combination with an excavator having e. digging tool. of a signalsystem for notifying 5 the operator by means oi a steadily increasingintenses' oi signal when the tool approaches toward a service member,said signal syst-2in comprisng a signal device, means connecting: one

side oi said signal device electrically' to said' tool,

l a source oi current for said signal device, means for detachablyconnecting the other side oi said signal device throufh sind source ofcurrent to a service member, a conductor for connecting said one side oisaid signal device also to said service l5 member, and a pilot lampconnected in said con# ductor'due to the connection oi said one side oisaid signal device through said tool and the earth to the service memberin parallel with said lamp.

2O G. In a sicnzil system for excavators, a source` of electricalenergy, a signal circuit connected to be energized therefrom, a signaldevice included in a part oi said circuit, said circuit also includingconducting: means for connection to a service member md additionalconducting means for connection to the tool of the excavator. the earthbetween the tool and the service member also beine, included in saidcircuit. the current in signal circuit being gradually increased as saidtool approaches the service member, whereby the signal intensity oi saidsignal de. vice also gradually increases, the signal commencing audibleoperation when the tool is at a substantially predetermined distancefrom the service member..

7. In a signal system for excavators, a source of electrical energy, asignal circuit -including means for producing electrical alternaiionssupplied from said source. said circuit having a por- 'iil tion thereofincluding conducting means for connection to a service xneinlier,together with a connection to the toot of the excavator, the earthbetween the tool and the service member being included in said circuitportion, said portion of said circuit being energized .from said meansfor producing electrical alternations, and a sin nai device coni-rolledfrom said circuit portion. the constants oi the circuit and thecharacter of the signal device being such that the signal is eiectivelyoperated at a predetermined distance of approach oi the digging tool tothe service member and is operated with increased intensiLr upon furtherapproach.

8. In combination with an excavator having a digcing tool, of a signalsystem for notifying the operator when the tool approaches a. buriedservice member, said signal system comprising a pair oi signal deviceshaving differing operating characteristics, circuit means forelectrically connecting said signal devices to said tool, a source ofcurrent for said signal devices, und means for electrically connecting,7said signal devices to a service member, the earth between said tool andthe service member completing the circuit (i5 for said signal devices,relay means for vrirying the Een of current through raid .'gmi devicesto cause the indication of one oi said devices to predominate when thetool is reli'itivcly remote from n service member, the signal output ofsaid device coniinuinr u'iih increased intcnsiy upon further approach ofthe tool until tlze Latter is at a predetermined distance from. theservice member', vv .'hcreupon the signal output oi said one devicefalls cil sharply and the signal output. of the other deviceprcdorninntes when the ooi continues to advance relatively close to theser vice member.

9. In combination vwith an excavator having a digging tool, oi a signalsysteml for notifying the operator when the tool approaches a buriedservice member, said signal system comprising a pair of signal devices odiiicring operating characteristics, a series multiple circuit havingsaid signal devices respectively connected in the respec ve parallellegs theresf, a source oi current connected in the series portion ofsaid circuit, said circuit series portion having one side thereofarranged for removable connection to a service member and the other sidethereof connected to said digging tool, the earth between said tool andthe service member completing the circuit for said signal devices, theconstants of the circuit and the character oi' the signal de vices beingsuch that the signal devices are eiiectiveiy operated at predetermineddistances of approach oi the digging tool to the service .inember, saidsignal devices operai-ing vwith dzierential intensities upon furtherapproach.

i0. In combination with an excavator having s diggin@ tool, of a signalsystem for notifying ie operator when the toolapproaches a buriedservice member, sai-:l signal system comprising a.

pair of signal devices, a series multiple circuit having said signaldevices respectively connected in the respective parallel legs thcreot',a source of current connected in the series portion ci' said circuit,said circuit series portion having eine side thereof arranged Iorremovable connection to a service member and theother side thereofconnected to said digging tool, resist-ors arranged .to be included insaid parallel legs, and relay means, 'responsive to the current-Serv inthe series portion 'oi said circuit, and operating, when the currenttherethrough reaches a predetermined value, for sliunting a resistorofone of said legs while inserting a resistor of the other leg therein.

11. in combination with an excavator having a digging tool, of a signalsystem ier Vnotifying the operator vwhen the trol approaches a hiddenservice member, said signal system comprising an oscillator, circuitmeans energized from said oscillator, said circuit means including saiddigging tool and an available service member in series therein, theearth between-said digging tool and the service member constituting apart of said circuit means, thei'mionic amplier controlled from the AiC. ousput of said circuit means, and a signal device connected in theoutput oi said amplier.

12. In combination with an excavator having a digging tool, of a signalsyst-em for notifying the operator when the too: rtg' coaches a hiddenservice member, said sional system comprising an audio oscillator,circuit-means including said digging tool, un available service memberand the intervening earth in `series therein, a transformer forsupplying energy from said oscillator to said circuit means, anamplifier having an audible signal device in the output thereof. and stransformer for coupling the A. C'. output of said circuit means to saidamplifier.

CHARLES I. MAUST.

